trats: Update TRATS config to support TIZEN download

trats: Update TRATS config to support TIZEN download

A set of environment variables needs to be updated to provide support for
TIZEN download command (tizendown).

Since DFU is used as a flashing backend, it is also necessary to extent
malloc pool size for DFU buffer allocation.
Moreover, for compatibility reasons (Win vs. Lin) new USB idProduct number
for download gadget had to be added.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Cc: Marek Vasut <marex@denx.de>